We see from MIME experience that the transition period will
be measured in years. It is now more than 2 years ago that the MIME
rfcs appeared in their first issue, and although MIME is spreading,
I see people turning back to other mail formats, after trying it,
and then being flamed for it. So MIME spreads even more slowly
than normal upgrading habits would expect.
I'm not sure this is different overall than could be expected. MIME tried to
avoid being hostile to the installed base, but given that the installed base
consisted of several different communities using mutually incompatible
conventions, there is no way that MIME could avoid being somewhat painful for
some groups of users.
However, on reflection it does appear that (in particular) quoted-printable
was not as well accepted as was anticipated. People who were used to seeing
correctly formed characters did not react favorably to instead seeing =XX,
even if =XX occurred seldom enough that the text could still be understood.
Thus my observation is that although MIME works fine between any two
MIME users, it does not work that well between a MIME user and a
non-MIME user. MIME then tends to be used accordingly, only between
MIME users, and there is thus a tendency to create a two-camp
world, MIME and non-MIME.
I think part of the problem is the lack of good free user agents for MIME. A
lot of user agents have been crudely patched to work with metamail. This is
a good first step, but not really sufficient to make the transition to MIME
with a minimum of pain. MH is a little bit better, but I still hear
complaints (from English-speaking people, no less!) about some of its
MIME-related quirks. exmh and pine are better, but many people don't want to
learn to use a new mail program!
(Another part of the problem is that we're still learning how to write
good MIME user agents...discovering how to deal with user interface issues
and legacy systems)
I am sure that MIME works, and a lot of other schemes would work also,
like Otha-san's, or some ISO 10646 encoding - if the sender and receiver
run compatible software, then there is no problem! The art of our
Internet design of new specifications is then to make it compatible
with the old.
That was why I created the mnemonic system some 4 years ago [...]
Keld, it's not clear that mnemonic is any friendlier to the installed base
(when taken as a whole) than either quoted-printable or ISO-2022-INT-*.
Mnemonic works for plain text in certain languages (but maybe not so well for
technical text or programming language source code). Ohta-san's approach
works okay for people who are displaying messages on terminals that support
ISO-2022 escape sequences. Either of them will work if there is appropriate
decoding/display software on the recipient end. Neither of them works well
for everyone, and neither of the schemes will work (without additional
encoding) for message headers.
Quoted-printable looked like a reasonable compromise when it was proposed,
but didn't look as good when it started cropping up everywhere. I'm not sure
that either mnemonic or iso-2022-int-* would fare any better when subjected
to the same scrutiny. Do your users like mnemnonic even if they were already
accustomed to seeing "the real thing" on their screens? Didn't they
complain when their real characters went away?
Or did your users have the luxury of having special software installed
(either at their MTA or UA) to handle mnemonic and translate it to their
local format? If so, it's not a fair comparison with quoted-printable.
I *like* mnemonic. I would like to see it widely implemented. If users
really like it enough better than bare MIME, it will become a de facto
standard, and everyone's mail user agent will support it. (Is there a
freely-available mnemonic<->8859/* translator that could be plugged into
.mailcap files? That would do more towards getting mnemonic to be accepted
than anything else...)
(By the same token, I think the ISO-2022-INT-* scheme is also clever, and
makes a good solution for a different set of people...but it isn't
sufficiently general to replace either quoted-printable encoding in message
bodies or 1522 encoded-words in headers.)
But the nice thing about MIME is that it is extensible enough to allow
new character sets and new content-types to be defined...
You can think of bare MIME as a "worst case" solution. It is somewhat ugly
and it is somewhat painful to migrate to it, but it is also very general and
it provides a smooth mechanism to migrate to future extensions. I fully
expect that in a few years, we won't be using the same content-types that we
typically use today...by then, "text/plain" may be relegated to shipping
around program source files, we will use something completely different for
human-readable text that provides a combination of multilingual character set
support, appearance information like (richtext,enriched,simpletext) tries to
provide now, and maybe semantic information also.
My recommendation is thus that we, when doing enhanced character set
support for news, then use the mnemonics scheme as our basic exchange
plain text format. This is currently also possible in MIME, and we should
use it there too.
I would like to see mail and news be as similar as possible. If you
can get *users* to embrace mnemonic, it should fit in just fine with
both mail and news -- if both are based on MIME.
But you may find that it takes more time to get widespread acceptance
of mnemonic, than it does to deploy real MIME mail readers!
Keith